Behind the quiet glow, a violent blast from the sun smashed into Earth’s magnetic shield, briefly rattling satellites, nudging radio systems and pushing the Northern Lights far beyond their usual Arctic home.
Solar punch that rattled Earth
On Monday, a massive surge of charged particles from the sun slammed into Earth, unleashing the most intense solar radiation storm seen in 23 years.
The event began when an X-class solar flare erupted from a large sunspot near the sun’s equator. That blast hurled a coronal mass ejection (CME) — a cloud of magnetised plasma — straight toward our planet.
The incoming solar eruption reached S4, labelled “severe” on the solar radiation storm scale — a level not recorded since the Halloween storms of 2003.
As the CME arrived, it ploughed into Earth’s magnetosphere, the invisible magnetic bubble that protects us from most solar and cosmic particles. The impact compressed this bubble and funnelled energetic particles deep into the upper atmosphere.
Space weather monitors quickly flagged a G4-level geomagnetic storm — the second-highest category — with conditions strong enough to disturb communications, threaten satellites and spark auroras far from polar regions.
Lights over Los Angeles: auroras reach unusual latitudes
Once the sun dipped below the horizon, skywatchers across the Northern Hemisphere found something extraordinary waiting for them.
Auroras rippled across the UK and much of Europe: France, Germany, Switzerland, Austria, Belgium, the Netherlands, Denmark, Norway and Croatia all reported colourful skies. Social media filled with photos of bright red bands and shimmering green curtains overhead.
In North America, forecasters had warned that auroras could spread across as many as two dozen US states. While the storm’s first peak arrived before dark in many places, the overnight display still reached strikingly far south.
➡️ Frost traps for squirrels: Expert explains why your help is urgently needed
➡️ Over 60? This is why your body reacts differently to stress now
➡️ Crêpes without butter, milk or eggs: the cheat-sheet of replacement ingredients to keep in your kitchen
➡️ The RSPCA urges anyone with robins in their garden to put out this simple kitchen staple today
➡️ Heating Off At Night: Clever Money Saver Or Costly Mistake For Your Energy Bill?
➡️ It seems king cobras, the world’s longest venomous snakes, have a taste for train travel
➡️ “I always felt behind,” until I stopped doing this one thing automatically
➡️ How to clean under couches without moving them fully
Reports came in from Alabama, Georgia, New Mexico and even Southern California, where residents caught rare glimpses of the Northern Lights above desert towns and coastal suburbs.
For many observers in these lower latitudes, it was a once-in-a-lifetime sight: faint but unmistakable arcs of colour stretching across the northern horizon, sometimes shifting and pulsing in real time.
What people actually saw in the sky
- Deep red glows overhead in central and northern Europe, including Vienna and Berlin
- Green and purple bands visible across parts of western France and the UK
- Soft, hazy arcs near the horizon in US states unaccustomed to auroras
- Brightening and fading “curtains” over northern latitudes as the storm fluctuated
Forecasters say more auroras remain possible while the sunspot region stays active, though the storm is not expected to hit the same intensity again immediately.
Record-breaking, but not the strongest in decades
The phrase “biggest storm in 23 years” can be confusing, because scientists track several different aspects of solar activity. This recent event did not beat the strength of the famous “Mother’s Day storm” of May 2024, which reached the top G5 “extreme” geomagnetic level.
What it did break is a different type of record: the intensity of the solar radiation streaming through space between the sun and Earth.
On that measure — the solar radiation storm scale — this event hit S4 strength, something not seen since 2003, making it the most powerful radiation storm in more than two decades.
By contrast, the 2024 Mother’s Day storm was driven by a rapid-fire sequence of at least five CMEs, which drenched Earth’s upper atmosphere in energetic particles for days. That prolonged bombardment caused widespread auroras and rewired parts of the planet’s radiation belts.
This new event was shorter and less disruptive overall, but more intense in terms of the particle flux racing through space at high energy.
How the scales work
| Scale | What it measures | Recent event level |
|---|---|---|
| G-scale (geomagnetic) | Impact on Earth’s magnetic field and systems like power grids and satellites | G4 – severe |
| S-scale (solar radiation) | Intensity of energetic particles streaming through space near Earth | S4 – severe |
In practice, a strong radiation storm often goes hand in hand with a strong geomagnetic one, but the exact impact on Earth depends on the direction and magnetic structure of the CME when it arrives.
What this means for technology and daily life
At G4 levels, a geomagnetic storm can trigger real, if usually short-lived, problems. Radio blackouts can hit high-frequency communications, especially near the poles. Airline routes may shift away from those regions to reduce radiation exposure and avoid patchy radio links.
Satellites feel the effects too. Charged particles can damage electronics, interfere with GPS accuracy and create additional drag that alters orbits, particularly for low-Earth orbit satellites like some weather and imaging platforms.
Power grid operators watch these storms closely, because rapid changes in Earth’s magnetic field can induce currents in long transmission lines and transformers.
Energy companies typically move into a higher state of readiness during major events, rebalancing loads or taking sensitive equipment offline if needed. So far, there have been no widespread reports of serious power disruptions linked to this storm.
Were people at risk?
For most people on the ground, the health risk from a storm like this is negligible. Earth’s atmosphere and magnetic field still shield us from the worst of the radiation.
The main concern lies with astronauts and high-altitude flights near the poles, where the protective magnetic field lines open and allow more particles to stream in. Space agencies and airlines receive dedicated space weather alerts so they can respond quickly when radiation levels increase.
Why the sun is so active right now
This storm is part of a broader pattern. The sun is approaching the peak of its 11-year activity cycle, known as solar maximum. During this phase, sunspots multiply, magnetic fields twist and snap, and both flares and CMEs become more frequent.
As the cycle climbs, the odds of strong geomagnetic and radiation storms rise too. Scientists expect more events of this kind over the next couple of years, though not every eruption will be pointed at Earth.
Space-weather centres around the world, including the US National Oceanic and Atmospheric Administration (NOAA), now track solar activity almost continuously with a fleet of spacecraft. Data from these observatories gives forecasters roughly 15 to 60 minutes’ warning once a CME reaches monitoring satellites upstream of Earth.
Key terms people keep hearing, explained
Solar storms come with a thicket of jargon, and those terms often get mixed in headlines. A few of the most common:
- Solar flare: A sudden flash of radiation from the sun’s surface, caused by magnetic energy release. It can disrupt radio signals on the dayside of Earth almost instantly.
- Coronal mass ejection (CME): A huge bubble of plasma and magnetic field ejected from the sun. If aimed at Earth, it can trigger geomagnetic storms and auroras when it arrives one to three days later.
- Solar radiation storm: A surge of fast, energetic particles travelling through space. This is what hit the S4 level during the latest event.
- Geomagnetic storm: The disturbance in Earth’s magnetic field caused when a CME or high-speed solar wind stream interacts with the magnetosphere.
What to do during the next big aurora night
With the sun so active, there is a fair chance of more widespread auroras over the next couple of years, even for regions far from the Arctic Circle. For anyone hoping to catch a display, a few practical points help.
- Find the darkest sky possible, away from city lights.
- Look north in the Northern Hemisphere, low on the horizon if you are far south.
- Give your eyes 20 to 30 minutes to adapt to the dark.
- Use a tripod and long exposure on your phone or camera, since faint auroras often show up better in photos than to the naked eye.
For businesses that depend on GPS, satellite services or long-distance radio, space weather bulletins are becoming as useful as normal weather forecasts. As events like this S4 radiation storm remind people, the sun is not just a distant bright disk in the sky. It is an active star, and every so often, it presses right up against the edges of our modern technology.